Photographic compositions and processes-b

ABSTRACT

Photographic developing agents which are lactone derivatives, such as coumarin derivatives, and especially 6-hydroxy coumarin and/or 6-amino coumarin derivatives, and, which have the property of forming a lactone developing agent precursor under neutral, slightly alkaline and acid conditions, provide less stain without loss of desired sensitometric properties in diffusion transfer systems. These are especially suitable in combination with other photographic developing agents. Corresponding developing agent precursors are also suitable in diffusion transfer systems. Stabilization processing systems can also employ these developing agents and/or developing agent precursors.

United States Patent [72] Inventor Edwin N. Oftedahl, Jr.

Rochester, N.Y. [21] App]. No. 764,301

[22] Filed Oct. 1, 1968 [45] Patented Oct. 26, 1971 [73] Assignee Eastman Kodak Company Rochester, N.Y.

[54) PHOTOGRAPHIC COMPOSITIONS AND PROCESSES-B 13 Claims, No Drawings [52] US. Cl 96/29, 96/66 [56] References Cited UNITED STATES PATENTS 2,603,659 7/1952 Raasch 96/66 X 2,698,236 12/1954 Land 96/29 2,698,237 12/1954 Land 96/76 2,698,238 12/1954 Land 96/29 FOREIGN PATENTS OTHER REFERENCES Treatment of Black-and-white Motion Picture Photomaterials, Khaikin, et al., U.S.S.R. 150,009, 9-14-62, Chemical Abstract, Vol.58, p, 4086 e.

Primary Examiner-William D. Martin Assistant Examiner- Theodore G. Davis AttorneysW. H. J. Kline, Bernard D. Wiese and Richard E.

Knapp ABSTRACT: Photographic developing agents which are lactone derivatives, such as coumarin derivatives, and especially 6-hydroxy coumarin and/0r 6-amino coumarin derivatives, and, which have the property of forming a lactone developing agent precursor under neutral, slightly alkaline and acid conditions, provide less stain without loss of desired sensitometric properties in diffusion transfer systems. These are especially suitable in combination with other photographic developing agents. Corresponding developing agent precursors are also suitable in diffusion transfer systems. Stabilization processing systems can also employ these developing agents and/or developing agent precursors BACKGROUND OF THE INVENTION 1. Field of the Invention" This invention relates to photographic developing agents and developing agent precursors and to photographic processingcompositions, especially developer compositions, elements and to processes utilizing such agents and' precursors. in one of its aspects, the invention relates to lactone derivative silver halide developing agents, such as hydroxy cinnamic acid and amino cinnamic acid compounds as photographic silver salt developing agents in developer compositions, processes and/or incorporated in photographic elements, especially those employed in diffusion transfer systems. in another of its aspects, the invention is directed to photographic developing agent precursors which are lactones, s,uch as hydroxy coumarins and amino coumarins in developer compositions and/or incorporated in photographic elements. A further aspect of the invention relates to photographic developer compositions such as viscous compositions designed for diffusion transfer processes containing such developing agents and/or developing agent precursors, e.g., amino cinnamic acid and/or hydroxy cinnamic acid silver ha- "lide developing agents, and/or hydroxy coumarin and/or amino'coumarin developing agent precursors, and to photographic diffusion transfer units comprising such developing agents and/or precursors.

2 Description of the Prior Art In recent years, diffusion transfer photographic processes, elements and compositions have become well known. The main advantage of the diffusion transfer process is that a positive print can be produced in a single step without resort to separate and inconvenient processing steps. Briefly, the diffusion transfer process is characterized by the use of a photographic emulsion layer and an image receiver or silver precipitating layer next to each other. After exposure of the photographic layer, typically a developer composition is applied between the exposed photographic layer and the silver precipitating layer. The developer composition usually contains a silver halide solvent, such as sodium thiosulfate, which causes the unexposed silver salts, usually silver halides, to dissolve forming a silver complex which diffuses to the image receiver or silver precipitating layer where development nuclei or a precipitating agent within that layer causes the silver to be precipitated from the silver complex. Development nuclei can be present in the image receiving layer before contact with the complexed silver or the nuclei can be formed in situ. Diffusion transfer photographic processes are well known and are described, for example, in U.S. Pat. Nos. 2,698,237 of Land issued Dec. 28, 1954; 2,647,056 of Land issued July 28, 1953; 3,108,001 of Green issued Oct. 22, 1963; and 3,345,166 ofLand issued Oct. 3, 1967.

The processing composition used in diffusion transfer processes normally contains the developing agent and is usually applied as a viscous fluid layer and spread between the photosensitive layer and the image receiving layer.

The requirements for diffusion transfer developing agents are very stringent and only relatively few of the developing agents which are satisfactory for general silver halide developin g processes will be satisfactory or active enough for diffusion transfer processes. One of the diffusion transfer developing agents used more successfully is 2,4-diaminophenol salts, and in particular 2,4-diaminophenol dihydrochloride, also known as Amidol. However, although such developing agents will produce a good positive image, they are subject to rapid oxidation which results in an unsightly and objectionable black oxidation product which stains the positive print unless removed.

Thus there has been a need for a developing agent which provides the desired sensitometric properties and developing action without objectionable stain.

There has also been a need for developing agents and/r developing agent precursors which are so-called acid quenchable. Developing agents and/or developing agent precursors which are acid quenchable include such compounds which have the property of providing desired developing action in the presence of a development activator and, when the desired degree of development is reached, such developing action can be stopped by lowering the pH and thus quenching the developing action by converting the developing agent to a developing agent precursor form. Developing agents whichare acid quenchable and which have a ring closure mechanism to form a developing agent precursor have not been previously known. I v.While the synthesis and chemistry of lactone compounds which have a ring opening and closure mechanism under respectively alkaline and .acid conditions are known, such as coumarins, no lactones have been reported in photographic elements, compositions and/or developing agent precursors. For example, the synthesis and chemistry of coumarins is described by S. M. Sethma and N. M. Shah, Chemical Reviews, 36, l, (1945); R. C. Elderfield, compounds, Volume 2,'Pages 173-216 (1951 and by R. Adams, Organic Reactions, Volume VII, Pages 1-58 (l953);61 these compounds have not been employed heretofore in photographic elements or in diffusion transfer developer compositionsand processes as socalled blocked developing agents or developing agent precursors. The use of 7,88-dihydroxy coumarin. as a developing agent per se is described in U.S.S.R. Pat. No. 150,009 issued Sept. 16, 1962 (Chemical Abstracts, Volume 58, P4086e). British Pat. Nos. 767,70lKodak discloses a 3-pyrazolidone developing agent with certain developing agents including 3,4- dihydroxy coumarin which like 7,8-dihydroxy coumarin has an ene-diol structure. However, no indication is given that lactones, and especially coumarin compounds can be employed as incorporated developing agents or precursors or that they can be used as a diffusion transfer developing agent or precursor.

Also, coumarin compounds have been employed in photographic emulsions as sensitizers such as disclosed in French Pat. No. 1,349,658. However, such compounds are not developing agents or developing agent precursors.

Accordingly, it is an object of the invention to provide improved photographic products, elements, developer compositions and developing processes, especially those employed in diffusion transfer systems, in which developing action can be essentially stopped by a mild acidic quench.

It is a further object of the invention to provide improved photographic diffusion transfer products, elements, processing compositions, especially developer compositions, and processes which provide images having desired sensitometric properties with reduced stain employing the described developing agents and developing agent precursors.

It is also an object of the invention to provide improved photographic elements and processing compositions containing hydroxy cinnamic acid and/or amino cinnamic acid developing agents, and/or hydroxy coumarin and/or amino coumarin developing agent precursors which provide images having reduced stain.

It is still a further object of the invention to provide improved photographic processes, especially diffusion transfer processes, utilizing the described photographic compositions and elements.

SUMMARY OF THE INVENTION According to the invention reduced stainedwithout loss of desired sensitometric properties is provided in diffusion transfersystems employing photographic products,-elements, processing compositions, especially developer compositions and processes, with a developing component which'is a lactone derivative silver halide developing agent which has the property of forming a lactone developing agent precursor under neutral, slightly alkaline and acid conditions, e.g., a pH about 9 or below and/or a lactone silver halide developing agent precursor which has the property of forming a lactone derivative silver halide developing agent in the presence of an alkaline development activator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A wide range of lactone derivative silver halide developing agents which have the property of forming a lactone silver halide developing agent precursor under neutral and acid conditions can be employed according to the invention. These include any lactone derivatives which provide desired developing activity and reduction of stain without adversely affecting desired maximum density, minimum density, photographic speed and other desired sensitometric properties. Suitable lactone derivative developing agents include those which under neutral, slightly alkaline or acid conditions, i.e., when the pH is lowered to a level of about 9 or lower, i.e., about 2 to about 9, do not have significant developing activity, if any, due to formation of a developing agent precursor.

The mechanism involved is believed to be the opening and closing of an anhydro ring in lactone compounds depending on pH conditions. For instance, in the case of a 6-hydroxy coumarin and/or 6-amino coumarin developing agent precursor, under alkaline conditions such as at a pH of about to about 14, the anhydro ring of such a lactone is believed to open forming a cinnamic acid developing agent, i.e., a coumarin derivative developing agent. This cinnamic acid developing agent has good developing properties and forms oxidation products which provide very little or no stain.

A wide variety of hydroxy cinnamic acid and/or amino cinnamic acid developing agents can be employed according to the invention. Suitable hydroxy cinnamic acid or amino cin namic acid developing agents include any such compounds which cause reduction cause a photographic silver salt in exposed areas ofa layer containing such photographic silver salt without adversely afiecting the unexposed areas of the photosensitive silver salt. Especially suitable developing agents are derivatives of 6-hydroxy coumarins, 6-amino coumarins, mixtures thereof and their salt, e.g. water soluble salts. Suitable cinnamic acid developing agents of the invention include compounds of the formula:

wherein:

a. R and R are individually hydrogen, halogen, e.g., chlorine, bromine or iodine, or alkyl, e.g., alkyl containing one to five carbon atoms such as methyl, ethyl, propyl, butyl and pentyl;

b. R; and R are individually hydrogen, alkyl, e.g., alkyl containing one to eight carbon atoms such as methyl, ethyl, propyl, butyl and pentyl, alkoxy, e.g., alkoxy containing one to five carbon atoms such as methoxy, ethoxy, propoxy, butoxy and pentoxy, halogen, as described, and aryl, e.g., aryl containing up to carbon atoms, such as phenyl, tolyl and xylyl;

c, R and R are individually hydroxy, hydrogen, amino, i.e., NH NHR or NRR wherein R and R are alkyl containing one to five carbon atoms, such as methyl, ethyl, butyl and pentyl; alkyl containing one to five carbon atoms, as described alkoxy containing one to five carbon atoms, as described, described, e.g., aryl containing up to 20 carbon atoms such as phenyl, tolyl, xylyl, mixtures thereof, and their salts, e.g., acid salts such as chloride, hydrochloride and sulfate salts and alkali metal salts such as potassium and sodium salts. Water soluble salts are suitable, as described.

Esters such as alkyl esters containing one to five carbon atoms, typically a methyl ester, ethyl ester, propyl ester, or butyl ester of the described cinnamic acid compounds, e.g., those within struct ire l ire also developirgagents. However, if an ester of a compound of structure I is formed this can hinder or prevent the formation ofa developing agent precursor as described. Accordingly, in some cases it can be undesirable to include compounds in a photographic element, composition or process according t6 the invention which cause formation of esters, typically alkyl esters of the described cinnamic acid developing agents.

Suitable cinnamic acid developing agents include:

Beta-4-dimethyl-2,5-dihydroxy cinnamic acid;

4-methyl-2,5-dihydroxy cinnamic acid;

6-bromo-4-methyl-2,5-dihydroxy cinnamic acid; 2-hydroxy-5-amino cinnamic acid;

Beta-methyl-2-hydroxy-4-methoxy-5-amino cinnamic acid;

Beta,4-dimethyl-2-hydroxy-5-amino cinnamic acid;

Beta-methyl-2,5-dihydroxy-4-methoxy cinnamic acid;

2-hydroxy-5-methylamino cinnamic acid;

2-hydroxy--5-anilino cinnamic acid;

4-t-butyl-2,5-dihydroxy cinnamic acid;

2,5-dihydroxy cinnamic acid;

2,5-dihydroxy-3,4,6-trimethyl cinnamic acid; and

2,3-dihydroxy cinnamic acid.

Similarly, corresponding derivatives of lactone developing agent precursors can be employed, which are derivatives of lactones containing a S-membered anhydro ring rather than a 6-membered anhydro ring as in coumarins. These include, for example, derivatives which are developing agents of the formula:

wherein R,, R R R R and R are as described for structure Also included are compounds which are derivatives of 3,4- dihydrocoumarins. These include compounds of the formula:

(III) wherein R R R2,, R R, are as described for structure 1. Examples of compounds within structure III include:

, CHCH:COOH

Also a wide range of lactone silver halide developing agent precursors can be employed which have the property of forming a lactone derivative silver halide developing agent in the presence of an alkaline development activator, e.g., under alkaline conditions including a pH of about to 14, typically a pH of about 12-14,. Suitable lactone developing agent precursors include any lactones which in the presence of an alkaline development activator have the property of forming a lactone derivative silver halide developing agent, typically, it is believed, by opening of the anhydro ring of the lactone, and in the presence of such a development activator provide desired developing activity and reduction of stain without adversely affecting desired maximum density, minimum density, photographic speed and other desired sensitometric properties.

Suitable hydroxy coumarins and amino coumarins which are developing agent precursors according to the invention include developing agent precursors of the formula:

R4 1 (IV) wherein R R R R R and R are as described for structure 1.

Suitable amino coumarins and/or hydroxy coumarins which, for example, can be employed according to the invention include:

8-hydroxy coumarin;

6-hydroxy-5,7-dimethoxy coumarin;

6-hydroxy-4,7-dimethyl coumarin;

6-hydroxy-5,7-diethoxy-4-methyl coumarin;

6-hydroxy coumarin;

8H-hydroxy-4-methyl coumarin;

6-hydroxy-4-methyl coumarin;

6-hydroxy coumarin-S-sulfonic acid;

o-hydroxy coumarin-S-sulfinic acid;

4,6-dihydroxy coumarin;

8-amino coumarin;

r 6-amino coumarin;

6-amino-5 ,7-dimethoxy coumarin;

8-amino-4-methyl coumarin;

6-amino '5 ,7-diethoxy-4-methyl coumarin;

6-amino-8-hydroxy coumarin;

6-hydroxy-8-amino coumarin and the like.

Other suitable lactone silver halide developing agent precursors include those containing a S-membered anhydro ring. These include, for example, lactones which are developing agent precursors of thgf o rmula:

wherein R R R R and R311 as described for structure I,

with the exception that R can also be aryl, as described, espe- 6 cially phenyl, tolyl or xylyl. Examples of developing agent precursors within structure lV-include:

and

Other suitable lactone developing agents, as described, include 3,4-dihydrocoumarin developing agent precursors corresponding to the coumarindeveloping agent precursors of structure IV. Examples of 3,4-dihydrocoumarin developing agent precursors include:

6,7 -dihydroxy-4-methyl-3,4-dihydrocoumarin and 7,8-dihydroxy-4-methyl-3,4-dihydrocoumarin. I

The developing agents and/or developing agent precursors of the invention are suitable in a range of physical locations in a diffusion transfer photographic system. They can be employed in one or more layers ofa photographic element and/or in a processing composition if desired. For example, they can be employed in a developer composition, such as an aqueous alkaline developer solution,or they can be incorporated into a layer of a photographic element, such as a silver halide emulsion layer, or overcoat layer. They can be employed in one or more layers ofa photographic element and/or developer composition intended for use in a diffusion transfer system. Suitable diffusion transfer systems, processes, developer compositions and elements therefor are described, for example,in U.S. Pat. Nos. 2,352,014 of Rott issued June 20, 1944; 2,453,181 of Land issued Feb. 27, 1951; and 3,337,342 of Green issued Aug. 27, 1967. They can be used also in so-called high-speed diffusion transfer processes as described, for example, in U.S. Pat. No. 3,326,683 of Land et al. issued June 20, 1967; or in other type of diffusion transfer processes such as those described in U.S. Pat. Nos. 2,857,274 of Land et .al. issued Oct. 21, 1958; 3,020,155 of Yackel et al. issued Feb. 6, 1962; 2,584,030 of Land issued Jan. 29, 1952; and 2,923,623 of Land issued Feb. 2, 1960. These also describe typical photographic products suitable for diffusion transfer systems comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and, typically, a silver halide developing agent, and (c) an image receiving layer.

The lactone derivative developing agent is typically selected from coumarin derivatives, mixtures thereof,.and their salts, e.g., cinnamic acid developing agents within structure I, especially derivatives of 6-hydroxy coumarins, 6-amino coumarins, mixtures thereof, and their salts.

Upon treatment with an alkaline activator, it is believed the lactone ring of the described coumarin compounds, for example, opens to yield a hydroxy group ,and thus a strong developer. The developing action can be stopped, or returned to its initial precursor form, which in some cases can .possess a weak developing paaf fF returning the dzveloping agent .form to the developing agent precursor .form by treatment with an acid, e.g., usually a mild acidic solution, such as an aqueous acetic acid, carbonic acid, hydrochloric acid, boric acid or nitric acid solution. This propertyis referred to as acid quenching and is especially useful in photographic processes 0 where residual oxidation or developer activity is undesirable.

The foregoing relationship or reaction can be illustrated by the .following equation employing coumarins as an example:

Clunamlcacld form coumarin form form the coumarin preferably has a hydroxy group or an amino group or a derivative of these groups which is in'the 6 position (i.e., R and/or 8 position (i.e., R i.e., located para or ortho, in the cinnamic form, to the unblocked hydroxy group.

Since the described developing agents and/or developing agent precursors can be employed in a range of locations in a diffusion transfer system one of the embodiments of the invention is in a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent, and typically, a silver halide developing agent, and (c) an image receiving layer the improvement comprising a lactone silver halide I developing agent which has the property of forming a lactone developing agent precursor under neutral, slightly alkaline and acid conditions. A photographic product is especially suitable wherein the lactone derivative is selected from the group consisting of coumarin derivatives, mixtures thereof, and their salts.

A suitable photographic element according to the invention comprises a layer containing a silver halide developing agent and/or precursor as described.

Part of the described developing agents and/or precursor can be present in the photographic element and part present in a photographic processing composition, e.g., an otherwise conventional photographic developer composition employed in diffusion transfer systems.

The lactone derivative silver halide developing agents and lactone developing agent precursors, e.g., coumarin or coumarin derivatives used in the practice of the invention can be prepared by conventional methods well known to the art or by obvious modifications of such methods to obtain derivative or substituted products. Various methods for preparing a given coumarin, as described, can, for example, be obtained from the following sources:

7-methyl-6-hydroxy coumarin-Desni and Mavani, Proc. Indian Acad. Sci., 25A, 327 (1947);

4,7-dimethyl-6-hydroxy coumarin-Desni Prac. Indian Acad. Sci., A, ll (1942);

6-amino coumarin--G. Morgan, J. Chem. Soc, Transactions 85, 1233 (1904); and 6,7-dihydroxy-4-methyl coumarin-Org. Syn., 4, 45 (1924). Further preparations can be obtained from the prior art and the described references.

The hydroxy cinnamic acids and/or amino cinnamic acids and their salts can be prepared by known processes or, as in the practice of the invention, by the alkalation of the respective coumarin.

The described developing agents and developing agent precursors according to the invention can be employed directly in the photographic element in any of a wide variety of photographic emulsions and/or in other layers of a photographic element. Typically, these compounds can be employed in a silver salt emulsion layer, an overcoat layer, a layer under the emulsion layer, a baryta layer, an antihalation layer, or virtually any later contiguous to the silver salt to be developed. For instance, the developing agents and/or developing a g eEprecursors of the invention can be employed in a photographic element having a layer containing:

a. a silver halide developing agent which is a hydroxy cinnamic acid or an amino cinnamic acid, and/or b. a silver halide developing agent precursor which is a hydroxy coumarin or an amino coumarin and a silver halide emulsion layer.

The developing agents and/or developing agent precursors described can be employed for developing an image in a wide range of photographic emulsions. They can be employed in such emulsions if desired. The photographic emulsions employed according to the invention can be X-ray or other nonspectrally sensitized emulsions or they can contain spectral sensitizing dyes such as described in U.S. Pat. Nos. 2,526,632 of..Brooker et al.,issued Oct. 24, 1950 and 2,503,776of Sprague issued Apr. 11, 1950. Spectral sensitizers which can and Mavani,

be used include cyanines, merocyanines, styryls and hemicyanines.

Various photographic silver salts can be used in the practice of the invention. These include photographic silver halides such as silver iodide, silver bromide, silver chloride, as well as mixed halides such as silver bromoiodide, silver chloroiodide and the like. Photographic silver slats which are not silver halides can also be employed such as silver salts of certain organic acids such as silver behenate.

The photosensitive coatings or receiving layers which are processed with the developing agents of the invention and/or contain the developing agents and/or developing agent precursors of the invention can be coated on a wide variety of supports. Suitable supports include those generally employed for photographic elements, such as, for example, cellulose acetate films, cellulose nitrate films, polyethylene terephthalate films, or other polyester films, polycarbonate films and related films or resinous materials; as well as papers, such as paper supports coated with resinous materials, e.g., coated with polyethylene, polypropylene and/or ethylene-butene copolymers; glass; metal, and the like. The supports or layers coated on them can contain fluorescent brightening agents, such as stilbenes, benzothiazoles, and benzoxazoles. Some of the coumarin compounds described can act as brightening agents.

The photographic elements processed according to the invention typically contain an emulsion layer comprising any of the known binding materials suitable for photographic purposes. These include natural and synthetic binding materials generally employed for this purpose, for example, gelatin, colloidal albumin, water soluble vinyl polymers, such as mono and polysaccharides, cellulose derivatives, proteins, water soluble polyacrylamides, polyvinyl pyrrolidone and the like as well as mixtures of such binding agents. The elements can also contain stripping layers and/or antistatic layers (i.e., conducting layers).

The developing agents and/or developing agent precursors of the invention can be employed in combinations with addenda known in the art to be useful in and/or for processing photographic elements. For instance, the photographic emulsions and compositions of the invention can contain various photographic addenda, particularly those known to be beneficial in photographic compositions. The various addenda and concentrations to be employed can be'determined by those skilled in the art. Suitable photographic addenda include hardeners, e.g., those set forth in British Pat. No. 974,317; buffers which maintain the desired developing activity and/or pH level, coating aids; plasticizers, speed increasing addenda, such as amines, quaternary ammonium salts, sulfonium salts, and alkylene oxide polymers; and various stabilizing agents, such as sodium sulfite. The photographic silver salt emulsions of the invention can also be chemically sensitized with compounds of the sulfur group such as sulfur, selenium and teelurium sensitizers, noble metal salts such as gold, or reduction sensitized with reducing agents or combinations of such materials.

The developing agents and developing agent precursors of the invention can be used in colloid transfer processes and elements such as described in U.S. Pat. No. 2,596,752 of Williams issued May 13, 1952. They can also be used in layers of photographic elements or in processing solutions intended for use in monobath processing such as described in U.S. Pat. No. 2,875,048 of l-laist et al. issued Feb. 24, l959, and British Pat. No. 1,063,844 of Beavers et al. published Mar. 30, 1967, and in web type processing, such as described in U.S. Pat. No. 3,179,517 ofTregillus et al. issued Apr. 20, 1965.

The developing agents and developing precursor agents of this invention are also used to advantage in multilayer, single element diffusion transfer processes which utilize the undeveloped silver halide in nonimage areas of the negative to form a positive by physical development of this silver onto a nuclei-containing lower layer after which the upper layer is removed by scrubbing, washing or stripping. Processes of this type are described, for example, in U.S. Pat. No. 3,020,155 of Yackel et al. issued Feb. 6, 1962.

Particularly good results, evidenced by improved tone and a desirable decrease in contrast, are obtained in elements of this type when they are processed by the use of an external processing web containing the developers of the invention in combination with a silver halide solvent and other processing or coating components dispersed in a vehicle and coated on a suitable support. Processing webs of this type have been described, for example, in U.S. Pat. No. 3,179,517 ofTregillus et al. issued Apr. 20, 1965.

The developing agents and developing agent precursors of the invention can be employed in photographic elements designed for processing in stabilization type processing. For example, they can be incorporated in one or more layers of a photographic element which is exposed, activated by contact with alkaline activator, and then contacted with a thiocyanate or thiosulfate solution, such as an ammonium thiocyanate or they can be incorporated in the alkaline activator. Such processes are described, for example, in U.S. Pat. No. 3,326,684 of Nishio et a1. issued June 20, 1967; British Pat. No. 1,004,302 of llford published Sept. 15, 1965; French Pat. No. 1,516,556 of Fassbender; and in an article by H. D. Russell et al. in the P.S.A. JOURNAL, Aug., 1950, Pages 59-62, entitled Stabilization Processing of Films and Papers."

The developing agents and developing agent precursors employed according to the invention also be present in one or more layers ofa photographic element designed for recording color images. For example, these compounds can be employed in one or more layers ofa photographic element containing a photographic layer sensitive to the blue region of the spectrum, a photographic layer sensitive to the green region of the spectrum, and a photographic layer sensitive to the red region of the spectrum. The layers sensitive to the blue, green and red regions of the spectrum can contain any suitable sensitizing dyes. Photographic elements designed for recording color images in which the developing agents and developing agent precursors of the invention are useful are described, for example, in Mees, The Theory of the Photographic process, 3rd Edition, Pages 382-396.

The developing agents and developing agent precursors of the invention can be employed in an element containing silver precipitating nuclei or development nuclei, e.g., an image receiver. As described, they can also be employed in photographic elements or processing compositions designed for use with an image receiver, e.g., a reception layer or receiving sheet which contains silver precipitating nuclei.

' Silver precipitating or development nuclei or agents which can be employed in diffusion transfer systems as described can be physical development nuclei or chemical precipitants including:

1. heavy metals in colloidal form and salts of these metals,

b. salts of amines which form silver salts and/or c. nondiffusion polymeric materials with functional groups capable of combining with the silver amine. Suitable sifir precipitating agents and/or nuclei within the above classes include metal sulfides, selenides, polysulfides, polyselenides, thiourea derivatives, stannous, hydroxy, silver, gold, platinum, palladium, and mercury, colloidal silver and similar agents disclosed, for example, in U.S. Pat. No. 3,020,155 of Yackel et al. issued Feb. 6, 1962. A wide range of concentrations of the silver precipitating agents and nuclei can be employed. The concentration of silver precipitant or nuclei in the receiving layer or receiving sheet must be at least sufficient to ensure a positive and sufficient removal of undeveloped silver salt from the light-sensitive layer to be processed. Usually, the concentration of developing agent and/or precursor described is about 3 to about 320 milligrams per square foot of the layer containing the precipitants or nuclei. 1

The developing agents and/or developing agent precursor of the invention can be employed in combination with any silver halide developing agent. The developing agents and/or developing agent precursors of the invention can be employed in such combinations as auxiliary developing agents or as the main components of the developing combination or developing precursor combination. Suitable silver halide developing agents which can be employed with the developing agent or developing agent precursor of the invention include, for example, polyhydroxybenzenes, such as hydroquinone developing agents, e.g., hydroquinone, alkyl substituted hydroquinones, as exemplified by t-butyl hydroquinone, methyl hydroquinone and 2,S-dimethylhydroquinone, catechol and pyrogallol; chloro substituted hyydroquinones such as chlorohydroquinone or dichlorohydroquinone; alkoxy substituted hydroquinones such as methoxy hydroquine; or ethoxy hydroquinone; aminophenol developing agents, such as 2,4-diaminopheuds and methylaminophenols; ascorbic acid, ascorbic acid ketals, such as those described in U.S. Pat. No. 3,337,342 ofGreen issued Aug. 22, 1967; hydroxylamines, such as N,N-di(2-ethoxyethyl)hydroxylamine 3-pyrazolidone developing agents such as l-phenyl-3-pyrazo1idone, including those described in Kodak British Pat. No. 930,572 published July 3, 1963; and acyl derivatives of paminophenol such as described in Kodak British Pat. No. 1,045,303 published Oct. 12, 1966. Such developing agents can be used alone or in combination with the developing agents or developing agent precursors of the invention.

The developing agents and/or developing agent precursors of the invention can be used in combination, for example, with the following compounds:

1-phenyl-3-pryazolidone hydroquinone methyl hydroquinone 2,5-dimethyl hydroquinone 2,6-dimethyl hydroquinone tertiary butyl hydroquinone 3,6-dihydroxy benzonorbornane 2,4-diamino-6-methyl phenol dihydrochloride 4-phenyl catechol tertiary butyl pyrocatechol 2,4-diaminophenol dihydrochloride ascorbic acid N-methyl-p-aminophenol sulfate N,N-ethylene di(oxymethyl)pyridinium perchlorate 2-(3-sulfopropyl)-2H-thiopseudo urea 7, l 4-diazo-6,l 5-dioxoeicosane- 1 ,21 perchlorate) These compounds, for instance can be incorporated in a photographic element employed in a diffusion transfer system, which after exposure can be developed employing a developer composition containing a developing agent and/or developing agent precursor of the invention.

-bis(phnidiniu'm One or more of the described combination of compounds can be in a photographic element and/or processing composition, e.g., developer composition of the invention. For example, a photographic element can contain a 3-pyrazolidone developing agent, such as l-phenyl-S-pyrazolidone and/or a 2,4-diaminopheno1 developing agent, such as 2,4-diamino-6- riiEFQifififiJfand/or 2,4-cHaminF6-methoxyphenol, and be developed employing a developer composition containing a developing agent and/or developing agent precursor of the invention, e.g., a 6-amino coumarin and/or 6-hydroxy coumarin, as described, such as 4,7-dimethyl-6-hydroxy coumarin.

The developing agents and/or developing agent precursors can be employed in a photographic silver salt emulsion designed for diffusion transfer processing and/or in a developer composition designed for developing and stabilizing the element. A typical developer composition is disclosed in U.S. Pat. 3,120,795 ofLand et al. issued Feb. 11, 1964.

Another embodiment of the invention is accordingly in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a viscous precessing composition comprising:

i. a silver halide solvent,

ii. an alkaline development activator,

iii. a 3-pyrazolidone developing agent or a diaminophenol developing agent,

iv. a -hydroxy coumarin derivative silver halide developing agent, and (c) an image receiving layer comprising development nuclei, especially palladium development nuclei, dispersed in a polymeric binder.

The developing agents and/or developing agent precursors of the invention can be employed in processing compositions in any form suitable for developing an exposed photographic element. For example, they can be employed as mixtures such as mixtures of the developing agents and/or developing agent precursors of the invention with auxiliary developing agents or they can be used as auxiliary developers with other developing agents. They can be supplied as an aqueous silver halide developer solution or liquid concentrate; as a component of a solid particulate composition suitable for dissolving in a solvent such as an aqueous solvent; as a viscous composition containing various thickening agents; as a packaged component of a kit for mixing with various processing agents or as a component of a fusible solid such as a solid containing a homogeneous of an alkaline oxide polymer and a developing agent precursor of the invention which melts above about room temperature, and the like.

Another embodiment of the invention is in a viscous liquid photographic developer composition comprising (a) a silver halide solvent, and (b) a silver halide developing component the improvement wherein said developing component is a lactone derivative silver halide developing agent which has the property of forming a lactone developing agent precursor under neutral and acid conditions. According to this embodiment a viscous liquid photographic developer composition, as described, can contain a lactone derivative, as described, which is a coumarin derivative, especially a 6-hydroxy coumarin and/or 6-amino coumarin derivative, mixtures thereof and their salts. A preferred embodiment is such a viscous liquid photographic developer composition also containing a second silver halide developing agent, as described, especially a 3-pyrazolidone silver halide developing agent. The second silver halide developing agent can be present in a greater proportion, by weight, than the described lactone derivative silver halide developing agent.

A viscous liquid photographic developer composition according to this embodiment can comprise a viscous monobath.-

Suitable viscous monobaths are described, for example, in the Monobath Manual, by Grant M. Haist (1966).

For instance, a suitable developer composition according to the invention can comprise a viscous developer containing:

a. a silver halide solvent, such as sodium thiosulfate,

b. a diaminophenol developing agent, such as 6-methoxy- 2,4-diaminophenol or 6-ethyl-2,4-diaminophenol or a 3-pyarzolidone developing agent, such as l-phenyl-3-pyrazolidone or l-phenyl-4,4-dimethyl-3-pyrazoldione,

c. a coumarin derivative silver halide developing agent, as

described, especially one of the formula:

R C=C-C OOH R5 OH I and/or a coumarin silver halide developing agent precursor of the formula:

R5 0 \o R0 wherein R,, R R Rj, and R are as described for structure I,

d. an alkaline development activator, and e.g.,

e. a thickening agent, such as a cellulose derivative, e.g., hydroxy ethyl cellulose and/or carboxy methyl cellulose.

A wide range of suitable viscosity can be employed. The viscosity is usually about 20 to about 1,000 cps. Various thickening agents are suitable in the described processing compositions and processes of the invention. Any of those commonly employed in diffusion transfer photographic systems can be employed. These include those described in the art, such as cellulose derivatives, e.g., hydroxy ethyl cellulose and/or carboxy methyl cellulose.

A photographic silver salt developer composition, according to this embodiment, typically can contain a hydroxy ethyl cellulose or carboxy methyl cellulose as the thickening agent, a silver halide developing agent, sodium hydroxide, potassium hydroxide or lithium hydroxide as the development activator and, for example, one or more cinnamic acid developing agents, i.e., coumarin derivatives selected from the following coumarins:

4,7-dimethyl-6-hydroxy coumarin;

8-hydroxy coumarin;

6-hydroxy-5,7-dimethoxy coumarin;

6-hydroxy-5,7-diethoxy-4-methyl coumarin;

o-hydroxy coumarin;

8-hydroxy-4-methyl coumarin;

6-hydroxy-4-methyl coumarin;

6-hydroxy coumarin-S-sulfonic acid;

6-hydroxy coumarin-S-sulfinic acid;

4,7,8-trihydroxy-4-methyl coumarin;

5,6,7-trihydroxy-4-nethyl coumarin; 6,7,8-trihydroxy-4-methyl coumarin; 5,6,7-trihydroxy-4-phenyl coumarin;

4,6-dihydroxy coumarin;

5,6-dihydroxy coumarin;

6,7-dihydroxy coumarin;

7,8-dihydroxy coumarin;

7-( benzyloxy)-6-hydroxy coumarin;

3,8-dibromo-6,7-dihydroxy-4-methyl coumarin;

5,6-dihydroxy-4,7-dimethyl coumarin; 7,8-dihydroxy-3,4-dimethyl coumarin; 7,7-dihydroxy-4-methyl coumarin;

I 7,8-dihydroxy-4-methyl coumarin;

6,77 -dihydroxy-4, -methyl-3-phenyl coumarin; and

6,7-dihydroxy-4-phenyl coumarin.

A further embodiment of the invention is in a photographic diffusion transfer process comprising developing a latent image in a photographic silver salt layer and precipitating an image on an image receiver layer the improvement comprising developing said latent image with a lactone derivative silver halide developing agent which has the property of forming a lactone developing agent precursor under neutral and acid conditions. This process is typically carried out at a pH about 10, e.g., ofabout 12 to about 14.

According to this embodiment a photographic diffusion transfer process can also comprise lowering the pH of the lactone derivative silver halide developing agent to about 9 or lower, e.g., about 2 to about 9, after precipitating an image on the image receiver layer. This is believed to convert the lactone developing agent to its precursor from, as described.

A photographic process according to the invention accordingly can comprise the steps of exposing a photographic element comprising a photographic silver salt layer to form a latent image therein, developing the latent image with a developer composition, at a pH of about 12 to about 14 comprising a 6-hydroxy coumarin or 6-amino coumarin derivative developing agent; contacting undeveloped silver salts in the photographic silver salt layer with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic, silver salt layer; transferring at least part of the silver complex to an image receiver layer contiguous to the photographic silver complex in the presence of development nuclei to form a visible image or said receiver layer; and lowering the pH of the developer compositions below about 9 to form a stable developed image.

Processing conditions, time of development, and the like can vary depending on the desired image, the particular components of the described element. processing composition. and image receiver. Typically processing is carried out under normal atmospheric conditions and is completed within about 60 seconds, e.g., within about 10 seconds. The process according to this embodiment can also employ a second silver halide developing agent, as described, in a layer of the photographic element processed and/or in the developer and/or developer precursor composition of the invention Usually the silver halide solvent will be sodium thiosulfate, however, various organic silver halide complexing agents such s as those described'by l-laist et al., hoto. Sci. Eng, 198 (1961) and in Kodak French Pat. No. 1,312,687 issued NO\ 12, 1962 and Belgian Pat. No. 606,559 of Ulrich et al. issued July 26, 1960, and similar agents can also be used.

The light-sensitive element, receiving element or processing composition can also contain toning agents such as. for exam ple, polyvalent inorganic salts of the type described in US. Pat. No. 2,698,236 of Land issued Dec 28, 1954. silica as described in US Pat. No. 2,698,237 of Land issued Dec 28, 1954, and heterocyclic mercaptans such as the mercapto azoles, e.g., mercapto diazoles. mercapto triazoles and mercapto tetrazoles.

As described, one of the advantages of the developing agents of the invention is that the developing action. which takes place upon contact of the developing agent precursor with a suitable activator, can be stopped by merely lowering the pH in the vicinity of the developing agent and thus returning the developing agent to its precursor form. Suitable alkaline development activators which can be used include those described and especially those which yield a pH of about 10.0 or greater Further development or oxidation can then be stopped thus preventing or substantially reducing developerstain, by lowering the pH of the developer to about 9 or lower As described, the lowering of the pH causes the hydroxy cinnamic acid and/or amino cinnamic acid, for example, to form its respective coumarin form which has only weak and usually negligible, developing activity, if any The activating pH according to this process should range from about 10 to 14, and best results are obtained when the pH is above about 12. The quenching pH range should be about from 9 to 2. The optimum pH for any system will in many cases also be influenced by the photographic element. the desired image, the various addenda used in the developer, emulsion or layers, etc.

The concentrations of the developing agents and/or developing agent precursors used in the practice of the invention can vary over wide ranges depending upon the particular photographic and physical variables present in the system for example, the position of the developing agent and/or developing agent precursors in the photographic element the developer composition, the desired image, CR. Suitable c-mcentrations are also dependent on processing conditions. addenda present in the photographic element to be processed and/or in the processing compositions Suitable optimum ton centrations can be easily determined by those skilled in the art through routine experimentation. Typically. when a develop ing agent according to the invention is employed in a photo graphic element. it is employed in the concentration of about 0.01 to about 5 moles of developing agent per mole of silver present in the photographic element. When a developing agent precursor is employed in a photographic element, it is typically employed in a concentration which provides about 0;0 l to about 5 moles of developing agent per mole of silver present in the photographic element upon activation Usually about 0.01 to about 5 moles of developing agent precursor per mole of silver present is SUfflCleltI When a developing ageni and/or developing agent precursor composition as described. is employed to process a photographic element. the total con centration of developing agents and precursors is tvpicalh about 0.01 to about i0. eg I to pr'cent by, weight of the total developer composition The parnt ulai developing time required can an over a wide :igt neiween a few seconds up to an hour or more. depending on the desired image. and the various addenda etc present. optimum developing time can also, however, be obtained by routine experimentation It is often advantageous to have an antifoggant present in the developer compositions of the invention and/or in the photographic element processed according to the invention. Suitable antifoggants include organic antifoggants. such as benzotriazole, benzimidazole, 2-mercaptobenzimidazole, nitro indazole, and mercaptotetrazole antifoggants. The developer compositions of the invention can contain an inorganic antifoggant. such as potassium bromide, potassium iodide and/or sodium bromide. The concentration of antifoggant in either the developer composition or element can be varied depending upon the desired image, other components present, subsequent processing steps and the like. The developer typically contains less than about 2 percent by weight ot the antifoggant and usually in the range of about 0 01 to 2 percent by weight Copending L S Pat. application Ser No. 764,358, of Oftedahl, filed concurrently herewith, titled Photographic Compositions and Processes-A" sets-out use of developing agents and/or developing agent precursors, especially 6- hydroxy coumarins and 6-amino coumarins described herein. with photographic elements, compositions, and processes in general The disclosure in this application is incorporated herein by reference. It willbe appreciated that the requirements for developing agents and/or developing agent precursors in diffusion transfer systems set out in the present application are very stringent compared to photographic systems in general.

A further understanding of the invention can be had from the following examples.

EXAMPLE 1 This example illustrates the invention.

A hydroxyethyl cellulose and t-butyl hydroguinone solution is prepared by dissolving 34 grams of hydroxyethyl in 700 ml. of water at C., cooling and purging the solution with nitrogen, and then admixing and dissolving 50 grams of sodium hydroxide and 20 grams of t-butylhydroquinone in the hydroxyethyl cellulose solution. A so-called hypohalide solution is prepared bydissolving 88 grams of sodium thiosulfate pentahydrate (NaSO '5H O), 1.0 gram of potassium iodide and 1.5 grams of sodium sulfite in 200 ml. of water and then purging the solution with nitrogen. The hydroxyethyl cellulose-t-butyl hydroquinone solution and the so-called hypohalide solution are mixed together and the volume adjusted to 1 liter by the addition of water. 0.0015 mole of 6-hydroxy-4- methyl coumarin is added to 10 milliliters of the resulting solution to produce a developer composition ofthe invention. This is done by squeezing the coumarin compound and the solutions back and forth between two connected syringes. The

resulting developer is a viscous liquid and is stored under nitrogen A photographic element 15 prepared by coating a high-speed silver bromoiodide photographic emulsion on a film support. An image receiver is prepared by coating a water resistant paper support with palladium development nuclei dispersed in a polymeric binder. The photographic element is sensitometrically exposed. The developer composition of the invention is then squeezed between the photographic element and the image receiver and the resulting so-called sandwich is pressed together by running it between two rollersv After 10 seconds, the sandwich is peeled apart and the resulting image on the image receiver is stabilized by applying a dilute aqueous hydrochloric acid solution to the image receiver to lower the pH to below about 9 A good positive image is produced with acceptable D min and D max values having low oxidation stain The results are set out in table I in following example 4.

Part of the photographic element is treated with a stop bath and a fixing bath And. part of the photographic element is untouched and allowed In darken in air for evaluation of stain 15 EXAMPLE 2 This is a comparative example.

The procedure set out in example 1 is repeated with the exception that the 6-hydroxy-4-methyl coumarin is omitted. The maximum density and contrast of the resulting image are lower than the image resulting from example 1.

EXAMPLE 3 EXAMPLE 4 This example and examples 5-12 illustrate the invention.

The procedure set out in example i is repeated with the exception that the coumarin compounds set out in column A of table I are employed in place of 6-hydroxy-4-methyl coumarm.

700 ml. of water at 60 C., cooling and purging the solution with nitrogen, and then admixing and dissolving 50 grams of sodium hydroxide and grams of 6-hydroxy-4,7hypohalide dime thyl coumarin in the hydroxyethyl cellulose solution. hypolhalide solution is prepared as described in example 1, by dissolving 88 grams of sodium thiosulfate pentahydrate (N,,SO 5H 0),l.O gram of potassium iodide andl.5 grams of sodium sulfite in 200 ml. of water and then purging the solution with nitrogen. The hydroxyethyl cellulose and developing agent solution and the so-called hypohalide solution are mixed together and the volume adjusted to 1 liter by the addition of water. 5 grams of l-phenyl-3-pyrazolidone is added per liter of the resulting solution to produce a developer composition of the invention. The resulting developer is a viscous liquid and is stored under nitrogen.

A photographic element and an image receiver are prepared as in example 1. The photographic element is sensitometrically exposed. The developer composition of the invention is then squeezed between the photographic element and the image receiver and the resulting so-called sandwich is pressed together by running it together between two rollers. After 10 seconds, the sandwich is separated.

A positive image is produced on the image receiver. Background stain is determined by reading reflectance of the minimum density area. The resulting positiveimage has a 77 TABLE I Positive print relative to control of Example 8 Oxidation stain Example N0 Dmax. Dmin.

3. Amidol (control) prior art 1.39 0.01 Dark (black). 1. 6-hydroxy-4-methyl coumarin F E Low (yellow). 4. Mixture of 3- and 5-bromo-7-methoxy-6-hy- G E Do.

dr0xy-4-methyl coumarin.

5. 7,8 dihydr0xy-4-methy1coumarin- S P Very low (yellow). 6. 4,7-dimethyl'6-arnino coumarin F E 7. 5-brorno-7-methyl-6-hydroxy coumarin G G Low (yellow). 8. 6,7-dihydroxy-4-rnethyl eoumarin E E o. 9. G-amino coumarin G F Medium (purple). 10. 4-methyl-6-amino-7-methoxy eoumari G E o. 11. 4,7-dimethyl-6-hydroxy coumarin- G E Low (yellow). 12. Mnethyl-6-hydr0xy-7-methoxy coumarin E E Do.

1 Dmax. expressed as:

S= Superior to control, i.e., 10% greater increase in density. E=Equal to control density. G= Good, i.e., less than 10% loss of density. F=Fair, i.e., less than 20% loss of density. 2 Dmin. expressed as:

E=Exeellent, Dmin. less than 0.03. G: Good, Dmin. between 0.04 to 0.06. F=Fair, Dmin. between 0.06 to 0.15. P=Poor, Dmin. between 0.15 to 0.25.

EXAMPLE 13 This example illustrates the invention.

The procedure set out in example 1 is repeated with the exception that 6-hydroxy-4,7-dimethyl coumarin is employed in place of 6-hydroxy-4-methyl coumarin and metal sulfide-silica development nuclei in a polymeric binder as described in US. Pat. No. 2,698,237 of Land issued Dec. 28, 1954, are employed in place of the palladium nuclei of example 1.

This results in a good image having little oxidation stain.

EXAMPLE 14 This example illustrates the invention.

The procedure set out in example 1 is repeated with the exception that 6-hydroxy-4-methyl-7-methoxy coumarin is employed in place of 6 -hydroxy-4-methyl coumarin and metal sulfide-silica development nuclei in a polymeric binder as described in US. Pat. No. 2,698,237 of Land issued Dec. 28, 1954, are employed in place of the palladium nuclei of example 1.

This results in a good image having little oxidation stain.

EXAMPLE 15 This example illustrates the invention. A hydroxyethyl cellulose and developing agent solution is prepared by dissolving 34 grams of hydroxyethyl cellulose in percent reflectance at 450 my" This illustrates that the coumarin derivatives of the invention can be employed as the main developing agent and a 3- pyrazolidone developing agent can be employed as a so-called auxiliary developing agent.

EXAMPLE 16 This is a comparative example.

The procedure set out in example 1 is repeated with the exception that 5 grams of l-phenyl-3-pyrazolidone per liter of total developer composition is employed in place of 6-hydroxy-4-methyl coumarin.

A positive image is produced on the image receiver. Background stain is determined by reading percent reflectance of the minimum density area. The resulting positive image has a 72 percent reflectance at 450 mu.

This illustrates that, surprisingly, higher stain is produced using (a) a combination of t-butyl hydroquinone as the main developing agent with l-phenyl-3-pyrazolidone as an auxiliary developing agent than (b) a combination of the invention which is a coumarin derivative developing agent as the main developing agent with l-phenyl-3-pyrazolidone as an auxiliary developing agent as described in example 15.

EXAMPLE 17 This is a comparative example.

The procedure set out in example l is repeated with the exception that 10 grams of 2,4-diamino-6-methylphenol per liter of total developer composition is employed in place of 6- hydroxy-4-methylcoumarin.

A positive image is produced on the image receiver. Background stain is determined by reading percent reflectance of the minimum density area. The resulting positive image has a 59 percent reflectance at 450 mu.

EXAMPLE l8 This example illustrates the invention.

The procedure set out in example is repeated with the bination (a) of t-butyl hydroquinone as the main developing agent with 2,4-diamino-6-methyl phenol as an auxiliary developing agent than (b) a combination of the invention which is a coumarin derivative developing agent as the main developing agent with 2,4-diamino-6-methyl phenol as an auxiliary developing agent.

EXAMPLE 19 This example illustrates the invention.

The procedure set out in example 15 is repeated with the exception that 2 grams of 2,4-diamino-6-methyoxy phenol per liter of total developer composition is employed in place of lphenyl-3-pyrazolidone.

EXAMPLE 20 This example illustrates the invention.

The procedure set out in example 15 is repeated with the exception that 5 grams of l-phenyl-4,4-dimethyl-3- pyrazolidone per liter of total developer composition is employed in place of l-phenyl-3-pyrazolidone.

A positive image is produced on the image receiver.

EXAMPLE 21 Similar results as in example 1 are obtained employing the following compound in place of the coumarin compound in example 1:

EXAMPLE 22 This example illustrates the preparation of 7-methyl-6- hydroxy coumarin.

In this example, 800 ml. of 85 percent by weight sulfuric acid is added to a mixture of 1 grams mole equivalent of 2- methylhydroquinone and 1 gram mole equivalent of malic acid. This solution is then heated on a steam bath for 4 hours.

The so-heated solution is then poured over ice to cause the 7- methyl--hydroxy coumarin to crystallize. The 7product is then collected, washed with water and then recrystallized from ethanol.

EXAMPLE 23 This example illustrates the preparation of 4,7-dimethyl-6- hydroxy coumarin.

In this example, 800 ml. of 73 percent (weight) sulfuric acid are added to a mixture of 1 gram equivalent of ethyl acetoacetate. The solution is then allowed to stand overnight in order to crystallize out the 4,7-dimethyl-6-hydroxy coumarin product. The product is then collected, washed with water and then recrystallized from ethanol and acetone.

EXAMPLE 24 This example illustrates the preparation of 5-bromo-7- methyl-o-hydroxy coumarin.

In this example, 8 grams of bromine in acetic acid is added to 9 grams of 7-methyl-6-hydroxy coumarin. A 5-bromo-7- methyl-6-hydroxy coumarin precipitate results. The precipitate is collected and then recyrstallized from acetic acid-liqroin to yield the 5-bromo 7-methyl-6-hydroxy coumarin product.

EXAMPLE 25 In this example, 6-amino coumarin is prepared by nitrating coumarin according to the method of G. Morgan, J. Chem. Soc., Transactions, 85, l233 (1904) and then reducing the reaction product'in ethanol using a palladium catalyst under 40 pounds of hydrogen.

EXAMPLE 26 in this example 4-methyl-6-amino-7-methyl coumarin is prepared by reducing 4-methyl-6-nitro-7-methyl coumarin in ethanol under 40 pounds of hydrogen pressure using a palladium catalyst.

EXAMPLE 27 in this example, 4,7-dimethyl-6-amino coumarin is prepared by reducing 4,7-dimethyl-6-nitro coumarin in ethanol under 40 pounds of hydrogen pressure using a palladium catalyst.

EXAMPLE 28 This is an example of the invention.

A hydroxyethyl cellulose and developing agent solution is prepared by dissolving 34 grams of hydroxyethyl cellulose in 700 ml. of water at 60 Q, cooling and purging the solution with nitrogen and then admixing and dissolving 50 grams of sodium hydroxide and 25 grams of 8-hydroxy coumarin in the hydroxyethyl cellulose solution. A so-called hypo-halide solution is prepared as described in example l, by dissolving 88 grams of sodium thiosulfate pentahydrate, 1.0 gram of potassium iodide and l.5-grams of sodium sulfite in 200 ml. of water and then purging the solution with nitrogen. The hydroxyethyl cellulose solution and developing agent solution and the socalled hypo-halide solution are mixed together and the volume adjusted to 1 liter by the addition of water. The resulting developer is a viscous liquid.

A photographic element and image receiver are prepared as in example i with the exceptions that the silver halide emulsion layer of the photographic element containing 50 mgJft. of 4-methyl-4-hydroxymethyl-3-pyraxolidone and the support is a water resistant paper. The photographic element is exposed sensitometrically. The developer composition is then squeezed between the photographic element and the image receiver from a pad, as described, for example, in the U.S. Pat. No. 2,698,237 of Land issued Dec. 28, 1954, and the resulting so-called sandwich pressed together. After 30 seconds the sandwich is separated.

A positive image is produced on the image receiver.

EXAMPLES 29-35 The procedure set out in example 28 is repeated with the exception that one of the following compounds in each instance is employed in place of 8-hydroxy coumarin.

In each case a positive image is produced in the image receiver.

-hydroxy-2-coumaranone EXAMPLE 30 5-hydroxy-3-phenyl-2-coumaranone EXAMPLE 3] 5-hydroxy-6-octyl-2-coumaranoe EXAMPLE 32 7-hydroxy'2-coumaranone EXAMPLE 33 6-Hydroxy-2-keto-l ,4-benzoxathian EXAMPLE 34 7,8-Dihydroxy-3-methyl-3,4-dihydrocoumarin EXAMPLE 35 7,8-Dihydro-4-methylcoumarin The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as set forth in the appended claims.

I claim:

1. In a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an imagere ceiimig layer, the improvement comprising a developing component in said processing composition comprising 2,5- dihydroxy cinnamic acid or 2-hydroxy amino cinnamic acid silver halide developing agent and a l-phenyl-3-pyrazolidone silver halide developing agent.

2. A photographic product as in claim 1 wherein said cinnamic acid silver halide developing agent is present in the rupturable container.

3. In a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an imagereceiving layer, the improvement comprising a developing component which is a hydroxy or amino cinnamic acid silver halide developing agent of the formula:

I Be

or a silver halide developing agent precursor of the formula;

wherein:

a. R and R are individually selected from the group consisting of hydrogen, alkyl containing one to five carbon atoms;

b. R and R are individually selected from the group consisting of hydrogen, alkyl containing one to five carbon atoms, alkoxy containing one to five carbon atoms, halogen and aryl containing up to 20 carbon atoms; and

c. R, and R are individually selected from the group consisting of hydroxy, amino, hydrogen, alkyl containing one to five carbon atoms, alkoxy containing one to five carbon atoms and aryl containing up to 20 carbon atoms; and mixtures thereof, and their salts; at least R is amino or hydroxy.

4. A photographic product as in claim 3 wherein said developing agent is present in said processing composition in a concentration of 0.01 to 10 percent by weight of said processing composition.

5. in a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an image-' receiving layer, the improvement comprising a developing component which is 2, 5 dihydroxy cinnamic acid or 2- hydroxy-S-amino-cinnamic acid silver halide developing agent. I

6. in a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an imagereceiving layer, the improvement comprising a silver halide developing agent selected from the group consisting of:

a. Beta,4-dimethyl-2,S-dihydroxy cinnamic acid,

b. Beta-methyl-Z,5-dihydroxy-4-methyoxy cinnamic acid,

c. Beta,4-diamethyl-2-hydroxy 5-amino cinnamic acid,

d. 2-hydroxy-5-amino cinnamic acid, and

e. Beta-methyl-4-methoxy-2-hydroxy-S-amino cinnamic acid.

7. A viscous liquid photographic developer composition comprising (a) a silver halide solvent and (b) a silver halide developing component, wherein said developing component is a hydroxy or amino cinnamic acid silver halide developing agent of the formula: wherein:

a. R and R are individually selected from the group consisting of hydrogen, halogen and alkyl containing one to five carbon atoms;

b. R;, and R are individually selected from the group consisting of hydrogen, alkyl containing one to five carbon atoms, alkoxy containing one to five carbon atoms, halogen and aryl containing up to 20 carbon atoms; and

c. R, and R are individually selected from the group consisting of hydroxy, amino, hydrogen, alkyl containing one to five carbon atoms, alkoxy containing one to five carbon atoms and aryl containing up to 20 carbon atoms; mixtures thereof, and their salts; at least R,, is amino or hydroxy. m

8. A viscous liquid photographic developer composition comprising (a) a silver halide solvent, (b) a silver halide developing component which comprises -2, S-dihydroxy cinnamic acid or Z-hydroxy-S-amino Lcinnamic acid silver halide developing agent and (c) an alkaline development activator.

9 A viscous liquid photographic developer composition comprising (a) a silver halide solvent, (b) a silver halide developing component which comprises -2,5-dihydroxy cinnamic acid or Z-hydroxy-S-amino cinnamic acid silver halide developing agent and a l-phenyl-3-pyrazolidone silver halide developing agent and (c) an alkaline development activator.

10. A viscous liquid photographic developer composition as in claim 9 which is a monobath.

11. A photographic process which comprises the steps of exposing a photographic element comprising a photographic silver salt layer to form a latent image therein; developing the latent image with a developer composition at a pH of about 12 to about 14 comprising -2,5-dihydroxy cinnamic acid or 2- hydroxy-S-amino cinnamic acid or 6-amino coumarin derivative developing agent; contacting undeveloped silver salts in the photographic silver salt layer with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic silver salt layer; transferring at least part of the silver complex to an image receiver layer contiguous to the photographic silver salt layer; reducing the silver complexin the presence of development nuclei to form a visible image on said receiver layer; and lowering the pH of the developer composition to below about 8 to form a stable developed image.

12. A process as in claim 11 also comprising developing said latent image with a 3-pyrazolidone developing agent or a diaminophenol developing agent.

13. A photographic process which comprises the steps of exposing a photographic element comprising a photographic silver salt layer to form a latent image therein; developing the latent image with a developer composition at a pH of about 12 to about 14 comprising a photographic silver halide developing agent selected from the group consisting of:

a. Beta,4-dimethyl-2,S-dihydroxy cinnamic acid,

b. Beta-methyl-2,5-dihydroxy-4-methoxy cinnamic acid,

c. Beta,4-dimethyl-2-hydroxy-5-amino cinnamic acid,

d. 2-hydroxy-5-amino cinnamic acid, and

e. Beta-methyl-4-methoxy-2-hydroxy-5-amino cinnamic acid; contacting undeveloped silver salts in the photographic silver salt layer with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic silver salt layer; transferring at least part of the silver complex to an image-receiver layer contiguous to the photographic silver salt layer; reducing the silver complex in the presence of development nuclei to form a visible image on said receiver layer; and lowering the pH of the developer composition to below about 8 to form a stable developed image.

* i t l Page 1 $2322 8?" UNITED STATES PATENT DFFICE CERTIFICATE OF CORRECTION Patent No. 3, 5, 43? Dated October 2 971 Inventor(s) Edwin N. Oftedahl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 2, line 20, after "Elderfield, insert ---Heterooyclic---. Line 20, "compounds" should read ---Compounds---.

In Column 2, line 22, before "these" delete "61".

In Column 2, line 26, "7,88-dihydroxy" should read --7,8-dihydroxy--.

In Column 2, line 29, "Nos." should read ---No.--.

In Column 5, line 3% "8Hhydroxy" should read --8-hydroxy--.

In Column 6, line 11, delete "agent precursors" and insert ---agents--.

In Column 7, line 7 1, "2,503,776of" should read S03:

In Column 8, line 7, "slats" should read ---salts---.

In Column 8, lines 55-56, "teelurium" should read -tellurium---.

In Column 9, line 55, "l. should read -a.-.

Page 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 5,159 D ed Ootober' 26, 1971 Inventofls) Edwin N. Oftedahl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 10, line ll "methoxy hydroqulne" should read ---methoxy hydroquinone--. q &

In Column 10, line 15, "2,J -diaminopheuds" should read ---2,L -diaminophenols--- In Column 10, line hl, "ascorbic acid" should go directly under "2,L -diaminopheno1 dihydrochloride" In Column 10, line hip, "ZH-thiopseudo" should read ---2-thiopseudo---.

In Column 10, line n5, "bis(phnidinium" should read --bis (pyridinium-.

In Column 10, line 71;, precessing" should read --processing.

In Column 11, line 75, delete "e.g.

In Column 12, line 28, "L ,7,8-trihydroxy-L -methyl coumerin; should read ---L ,7, B-trihydroxy ooumarin;---.

In Column 12, line 29, "5,6, Y-trihydroxy-h-nethyl ooumarin" should read ---5,6,Y-trihydroxy-h-methyl coumarin--- po-mso Patent No.

Inventor(s) Edwin N.

CERTIFICATE OF CORRECTION Dated October 26, 1971 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 12, line L O, "7,7-dihydroxy-Lp-methyl ooumar in" should read --6,Y-dihydroxy-Lp-methyl coumarin--- In Column In Column -Photo.--.

In Column In Column In Column In Column oellulose-.

In Column In Column so-oalled-.

In Column --hyponalide-.

line

line

line

line

line

line

line

line

line

before "as" delete "s".

after after after after hoto."

should read "exam" insert "element" insert "photo" insert "hydroxyethyl" insert 3, delete hypohalide" L after "solution." insert -A 5, "hypolhalide" should read Page )4.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,615,159 Dated October 26, 1971 Inventor(s) Edwin N. Oftedahl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 16, line 7, "(N so 5H 0)" should read ---*'NaSO -5H O)-. 2

In Column 17, line 31;, "methyoxy" should read --methoXy---.

In Column 17, line 36, after "phenyl-B-pyrazolidone." insert new paragraph --A positive image is produced on the image receiver. Background stain is determined by reading percent reflectance of the minimum density area. The resulting positive image has a 76% reflectance at 150 m L,---.

In Column 17, line 621, '1 grams" should read --1 gram--- 7 ,7

In Column 17, line 68, "7" Sh u d read crystallized In Column 18, line 16, "ac id-liqro in" should read ---acid-1igroin.

In Column 18, line 61, "pyraxolidone" should read -pyrazolidone---.

In Column 19, line 10, "coumaranoe" should read ---coumaranone-.

In the Claims In Column 19, line 70, after "hydrogen," insert --halogen and----.

Page 5 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,6l5,Li39 Dated October 26, 1971 Inventm-(s) Edwin N. Oftedahl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 20, line 27, "methyoxy" should read -methoXy--.

In Column 20, line 28, "diamethyl" should read ---dimethyl-.

In Column 20, line 36 after "formulaz" insert C COOH R5 OH or a silver halide developing agent precursor of the formula:

In Column ?O, line Si t, "Lo innamio" should read l Signed and sealed this 6th day of March 1973 (SEAL) Attost:

EDWARD M. PLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. A photographic product as in claim 1 wherein said cinnamic acid silver halide developing agent is present in the rupturable container.
 3. In a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an image-receiving layer, the improvement comprising a developing component which is a hydroxy or amino cinnamic acid silver halide developing agent of the formula:
 4. A photographic product as in claim 3 wherein said developing agent is present in said processing composition in a concentration of 0.01 to 10 percent by weight of said processing composition.
 5. In a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an image-receiving layer, the improvement comprising a developing component which is 2, 5 dihydroxy cinnamic acid or 2-hydroxy-5-amino-cinnamic acid silver halide developing agent.
 6. In a photographic product comprising in combination (a) a photographic element comprising a photographic silver salt layer, (b) a rupturable container containing a processing composition containing a silver halide solvent and (c) an image-receiving layer, the improvement comprising a silver halide developing agent selected from the group consisting of: a. Beta,4-dimethyl-2,5-dihydroxy cinnamic acid, b. Beta-methyl-2,5-dihydroxy-4-methyoxy cinnamic acid, c. Beta,4-diamethyl-2-hydroxy-5-amino cinnamic acid, d. 2-hydroxy-5-amino cinnamic acid, and e. Beta-methyl-4-methoxy-2-hydroxy-5-amino cinnamic acid.
 7. A viscous liquid photographic developer composition comprising (a) a silver halide solvent and (b) a silver halide developing component, wherein said developing component is a hydroxy or amino cinnamic acid silver halide developing agent of the formula: wherein: a. R1 and R2 are individually selected from the group consisting of hydrogen, halogen and alkyl containing one to five carbon atoms; b. R3 and R5 are individually selected from the group consisting of hydrogen, alkyl containing one to five carbon atoms, alkoxy containing one to five carbon atoms, halogen and aryl containing up to 20 carbon atoms; and c. R4 and R6 are individually selected from the group consisting of hydroxy, amino, hydrogen, alkyl containing one to five carbon atoms, alkoxy containing one to five carbon atoms and aryl containing up to 20 Carbon atoms; mixtures thereof, and their salts; at least R4 is amino or hydroxy.
 8. A viscous liquid photographic developer composition comprising (a) a silver halide solvent, (b) a silver halide developing component which comprises -2, 5-dihydroxy cinnamic acid or 2-hydroxy-5-amino cinnamic acid silver halide developing agent and (c) an alkaline development activator.
 9. A viscous liquid photographic developer composition comprising (a) a silver halide solvent, (b) a silver halide developing component which comprises -2,5-dihydroxy cinnamic acid or 2-hydroxy-5-amino cinnamic acid silver halide developing agent and a 1-phenyl-3-pyrazolidone silver halide developing agent and (c) an alkaline development activator.
 10. A viscous liquid photographic developer composition as in claim 9 which is a monobath.
 11. A photographic process which comprises the steps of exposing a photographic element comprising a photographic silver salt layer to form a latent image therein; developing the latent image with a developer composition at a pH of about 12 to about 14 comprising -2,5-dihydroxy cinnamic acid or 2-hydroxy-5-amino cinnamic acid or 6-amino coumarin derivative developing agent; contacting undeveloped silver salts in the photographic silver salt layer with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic silver salt layer; transferring at least part of the silver complex to an image receiver layer contiguous to the photographic silver salt layer; reducing the silver complex in the presence of development nuclei to form a visible image on said receiver layer; and lowering the pH of the developer composition to below about 8 to form a stable developed image.
 12. A process as in claim 11 also comprising developing said latent image with a 3-pyrazolidone developing agent or a diaminophenol developing agent.
 13. A photographic process which comprises the steps of exposing a photographic element comprising a photographic silver salt layer to form a latent image therein; developing the latent image with a developer composition at a pH of about 12 to about 14 comprising a photographic silver halide developing agent selected from the group consisting of: a. Beta,4-dimethyl-2,5-dihydroxy cinnamic acid, b. Beta-methyl-2,5-dihydroxy-4-methoxy cinnamic acid, c. Beta,4-dimethyl-2-hydroxy-5-amino cinnamic acid, d. 2-hydroxy-5-amino cinnamic acid, and e. Beta-methyl-4-methoxy-2-hydroxy-5-amino cinnamic acid; contacting undeveloped silver salts in the photographic silver salt layer with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic silver salt layer; transferring at least part of the silver complex to an image-receiver layer contiguous to the photographic silver salt layer; reducing the silver complex in the presence of development nuclei to form a visible image on said receiver layer; and lowering the pH of the developer composition to below about 8 to form a stable developed image. 